1. Field of the Invention
The invention relates to a workpiece clamping system for a measuring machine comprising a rotary table disposed in a workpiece rotation axis and comprising a chuck for the concentric accommodation of a workpiece, a rotary drive for the rotary table, an upper centering tip mountable or mounted on the measuring machine in the workpiece rotation axis vertically opposed to the rotary table and a lower centering tip for accommodating a workpiece between the centering tips instead of in the chuck mountable or mounted on the rotary table in addition to the chuck.
2. Discussion of the Related Art
A measuring machine in which a workpiece clamping system of the abovementioned type is used can be found, for example, in the company's catalogue “KLINGELNBERG P26/P40 Präzisionsmesszentren” comprising the publication information “DE 05/2013”. A measuring machine as shown in the appended drawings in FIG. 13 as the state of the art is, according to the description on page 4 of the company's catalogue, a precision measurement centre in which the measuring machine comprises a precision heavy-duty rotary table. It is embodied as a measuring axis (C axis) and concentrically accommodates workpieces to be examined in a workpiece rotation axis designated by 17 in the appended FIG. 13. In combination with three linear measuring axes, tangential (X-axis), radial (Y-axis), and vertical (Z-axis), illustrated in the figure on page 4 of the company's catalogue the measuring machine scans functional surfaces of indentations and generally driving components in the manufacturer mode and examines them with the highest measuring and reproduction precision.
In the Applicant's current P production series which is among the precision measurement centres P26 and P40 according to the abovementioned company catalogue, there are the options of clamping between tips (illustrated in the company's catalogue on page 4), the accommodation in the chuck (illustrated in the company's catalogue on page 12, image on the left in the second last row of images) or the direct placement of the workpiece on the rotary table (which is of no relevance here) for accommodating the workpieces. In a measuring machine as partly visible in the abovementioned left image on page 12 of the company's catalogue no upper centering tip is provided as a backing device so that clamping between the tips is inapplicable with this machine. In the machine according to page 12 of the company's catalogue, it is therefore envisaged that the workpieces to be measured are accommodated in a clamping system comprising a multi-jaw chuck.
In the illustration in the appended FIG. 13 corresponding to the illustration on page 4 of the company's catalogue an additional chuck 11′ in which short, symmetric workpieces are clamped is mounted on a rotary table 13. A lower centering tip 40′ indicated by dotted lines in FIG. 13 may also be concentrically mounted on the rotary table 13 in a column 19 concentrically mounted on the rotary table 13 and supporting the chuck 11′. If a workpiece is to be clamped between the upper centering tip 30 and the lower centering tip 40′ instead of in the chuck 11′ the measuring machine has to be converted in advance which consumes time. The conversion includes the removal of the chuck 11′ and the column 20 supporting the chuck 11′ so that the lower centering tip 40′ is made accessible or can be fixed on the rotary table 13. The latter case corresponds to the alternative that the lower centering tip 40′ is not accommodated in the column 19 but kept separately and only mounted on the rotary table 13 after the removal of the chuck 11′ and the column 19. In this case the conversion will cost even more time.
Such measuring machines are generally used in assembly lines as employed in automobile and utility vehicle industry as well as in aircraft industry. If different parts are to be produced in an assembly line the conversion of the measuring machine should be possible and automatable with less time expenditure. In addition, the solution comprising a lower centering tip disposed in a column under a chuck 11′ and to be made accessible only by the removal of the column and the chuck is not flexible.